In the communications field, OpenFlow is a protocol for controlling interactions between a controller and a switch in an architecture in which control is separated from forwarding. A switch for switching data according to the OpenFlow protocol is an OpenFlow switch, and interchangable OpenFlow negotiable datapath models (NDM) are files for describing functions of an OpenFlow switch.
A standardization organization or an enterprise publishes an NDM file, and the NDM file describes a function requirement of the standardization organization or enterprise for the OpenFlow switch. A device provider develops a corresponding OpenFlow switch according to the description of the NDM file, so that the developed OpenFlow switch has a function described in the NDM file.
The NDM file may be easily tampered with in a network transmission process. However, in the prior art, a receiving device cannot determine, according to content of the NDM file, whether the NDM file is tampered with in the transmission process, resulting in low security of the NDM file.